An inflatable cushion disposed within a supporting structure such as a dash panel, side door or other fixed portion of a car body in opposing relation to a seat in the vehicle plays an important role in protecting the occupants of a vehicle from injury due to collision against the car body. Typically, the inflatable cushion is inflated rapidly by the pressure of a reaction gas released from an inflator during a collision. This gas generation typically takes place when a gas generating agent in the inflator induces a chemical reaction by a collision signal from a collision detecting sensor when the deceleration of the vehicle exceeds a certain level. The gas generated by the generator is then conveyed to the inflatable cushion which expands outwardly as it fills with gas to create a protective barrier between the vehicle occupant and the dash panel or other portion of the vehicle body/internal surface against which the occupant might otherwise be thrown.
To elaborate, inflatable protective cushions used in passenger vehicles are a component of relatively complex passive restraint systems. The main elements of these systems are: an impact sensing system, an ignition system, a propellant material, an attachment device, a system enclosure, and an inflatable protective cushion. Upon sensing an impact, the propellant is ignited causing an explosive release of gases filing the cushion to a deployed state that can absorb the impact of the forward movement of a body and dissipate its energy by means of rapid venting of the gas. In the undeployed state, the cushion is stored in or near the steering column, the dashboard, in a door, or in the back of a front seat placing the cushion in close proximity to the person or object it is to protect.
Inflatable cushion systems, commonly referred to as air bag systems, have been used in the past to protect both the operator of the vehicle and passengers. Systems for the protection of the vehicle operator have typically been mounted in the steering column of the vehicle and have utilized cushion constructions directly deployable towards the driver. These driver-side cushions are typically of a relatively simple configuration in that they function over a fairly small well-defined area between the driver and the steering column. One such configuration is disclosed in U.S. Pat. No. 5,533,755 to Nelsen et al., the teachings of which are incorporated herein by reference.
Inflatable cushions for use in the protection of passengers against frontal or side impacts must generally have a more complex configuration since the position of a vehicle passenger may not be well defined and greater distance may exist between the passenger and the surface of the vehicle against which that passenger might be thrown in the event of a collision. Prior cushions for use in such environments are disclosed in U.S. Pat. No. 5,520,416 to Bishop, issued May 28, 1996; U.S. Pat. No. 5,454,594 to Krickl issued Oct. 3, 1995; U.S. Pat. No. 5,423,273 to Hawthorn et al. issued Jun. 13, 1995; U.S. Pat. No. 5,316,337 to Yamaji et al. issued May 31, 1994; U.S. Pat. No. 5,310,216 to Wehner et al. issued on May 10, 1994; U.S. Pat. No. 5,090,729 to Watanabe issued Feb. 25, 1992; U.S. Pat. No. 5,087,071 to Wallner et al. issued Feb. 11, 1992; U.S. Pat. No. 4,944,529 to Backhaus issued Jul. 31, 1990; and U.S. Pat. No. 3,792,873 to Buchner et al. issued Feb. 19, 1974, all of which are incorporated herein by reference.
However, a problem still exists in the prior art to adequately protect occupants of vehicles when the distance between the passenger and the origin of the air bag is greater than the comparative distance of a vehicle's driver and the steering column. Often the gap that needs to be filled cannot be adequately done with a straight deployment, leaving gaps. Even worse, an instrumental pane, can hinder a linearly deployed air bag, or alternately a linearly deployed air bag cannot move sufficiently upon deployment to protect an occupant. Air bags that do fill gaps between occupants and the vehicle frame, by necessity, have to be large, resulting in elaborated deployment and costing significantly more to make in both materials and manpower than the simple driver's side design. At the same time, solutions to these problems tend to sacrifice other important elements of inflatable cushion design such as simplified sewing patterns, product robustness and manufacturing cost.
Further, passenger airbags designed for top mount or ¾ mount applications require the airbag cushion to rotate in order to cover the instrument panel. In these applications, the depth of the module has a significant effect on the cushion design. In modules where the height differential from the top of the module to the attachment point of the cushion is minimal, slits may be provided in the bottom portion of the airbag cushion to cause rotation thereof. However, in the situation where the height differential is larger, the profile becomes difficult to adjust in order to cause bag rotation.
What is needed is an improved top-mounted or ¾ mounted inflatable cushion that will adequately protect vehicle occupants while at the same time keep relatively simple sewing patterns, good product robustness and minimize costs. It would also be desirable to provide an apparatus and method that allows a variety of airbag cushions to fit within a variety of airbag modules, so that such cushions may be adapted to be top mounted with respect to the instrumental panel or dashboard of an automobile. It would also be desirable to provide a device that may adjust the profile of a cushion in situations where the height differential between the top of the module and the attachment point of the cushion is significant.